A study published in the Proceedings of the National Academy of Sciences noted that Facebook allowed researchers to manipulate the positive and negative information that users saw on their News Feeds in order to test users' emotional responses to that content. The study was conducted from Jan. 11 to Jan. 18, 2012.
In the experiment, Facebook temporarily influenced the kind of posts and photos that about 700,000 of its English-speaking users saw in their News Feeds, making it possible for researchers to show either mostly positive comments and posts or mostly negative comments and posts.
That means users were not shown a regular cross-section of their friends' posts, but instead were given a manipulated feed. It also means that half of those users were purposefully shown data meant to see if it would make them sad.
The study found that people who saw more positive comments made more positive comments themselves, while users who saw more negative comments became more negative.
Users, analysts and the blogosphere has been in an uproar over the manipulation.
While analysts generally agreed that the experiment was not illegal, they also said it unfairly manipulated the company's users.
Sign up for CIO Asia eNewsletters.